Refactor: replace `getFieldFromAcroForm` with `from_AcroForm`, modernize impleme…

…ntation, and update references in `FormField` methods.

Refactor: replace `getFieldFromAcroForm` with `from_AcroForm`, modernize impleme…
…ntation, and update references in `FormField` methods.
m-holger
1 parent 4b08688f
Showing 3 changed files with 30 additions and 25 deletions
libqpdf/QPDFFormFieldObjectHelper.cc
libqpdf/qpdf/FormField.hh
libtests/objects.cc
@@ -18,6 +18,8 @@ using namespace qpdf;
 using FormField = qpdf::impl::FormField;
+const QPDFObjectHandle FormField::null_oh;
+
 class QPDFFormFieldObjectHelper::Members: public FormField
 {
   public:
@@ -79,22 +81,6 @@ FormField::root_field(bool* is_different)
 }
 QPDFObjectHandle
-FormField::getFieldFromAcroForm(std::string const& name)
-{
-    QPDFObjectHandle result = QPDFObjectHandle::newNull();
-    // Fields are supposed to be indirect, so this should work.
-    QPDF* q = oh().getOwningQPDF();
-    if (!q) {
-        return result;
-    }
-    auto acroform = q->getRoot().getKey("/AcroForm");
-    if (!acroform.isDictionary()) {
-        return result;
-    }
-    return acroform.getKey(name);
-}
-
-QPDFObjectHandle
 QPDFFormFieldObjectHelper::getInheritableFieldValue(std::string const& name)
 {
     return m->getInheritableFieldValue(name);
@@ -289,13 +275,13 @@ FormField::getDefaultValueAsString()
 QPDFObjectHandle
 QPDFFormFieldObjectHelper::getDefaultResources()
 {
-    return m->getDefaultResources();
+    return Null::if_null(m->getDefaultResources());
 }
 QPDFObjectHandle
 FormField::getDefaultResources()
 {
-    return getFieldFromAcroForm("/DR");
+    return from_AcroForm("/DR");
 }
 std::string
@@ -310,7 +296,7 @@ FormField::getDefaultAppearance()
     auto value = getInheritableFieldValue("/DA");
     bool looked_in_acroform = false;
     if (!value.isString()) {
-        value = getFieldFromAcroForm("/DA");
+        value = from_AcroForm("/DA");
         looked_in_acroform = true;
     }
     if (value.isString()) {
@@ -332,7 +318,7 @@ FormField::getQuadding()
     QPDFObjectHandle fv = getInheritableFieldValue("/Q");
     bool looked_in_acroform = false;
     if (!fv.isInteger()) {
-        fv = getFieldFromAcroForm("/Q");
+        fv = from_AcroForm("/Q");
         looked_in_acroform = true;
     }
     if (fv.isInteger()) {
@@ -173,12 +173,29 @@ namespace qpdf::impl
         void generateAppearance(QPDFAnnotationObjectHelper&);
       private:
-        QPDFObjectHandle getFieldFromAcroForm(std::string const& name);
+        /// @brief Retrieves an entry from the document's /AcroForm dictionary using the specified
+        /// name.
+        ///
+        /// The method accesses the AcroForm dictionary within the root object of the PDF document.
+        /// If the the AcroForm dictionary contains the given field name, it retrieves the
+        /// corresponding entry. Otherwise, it returns a default-constructed object handle.
+        ///
+        /// @param name The name of the form field to retrieve.
+        /// @return A object handle corresponding to the specified name within the AcroForm
+        /// dictionary.
+        QPDFObjectHandle const&
+        from_AcroForm(std::string const& name) const
+        {
+            return {qpdf() ? qpdf()->getRoot()["/AcroForm"][name] : null_oh};
+        }
+
         void setRadioButtonValue(QPDFObjectHandle name);
         void setCheckBoxValue(bool value);
         void generateTextAppearance(QPDFAnnotationObjectHelper&);
         QPDFObjectHandle
         getFontFromResource(QPDFObjectHandle resources, std::string const& font_name);
+
+        static const QPDFObjectHandle null_oh;
     };
 } // namespace qpdf::impl
@@ -90,7 +90,6 @@ test_0(QPDF&amp; pdf, char const* arg2)
     assert_compare_numbers(UINT_MAX, t.getKey("/Q3").getUIntValueAsUInt());
 }
-
 static void
 test_1(QPDF& pdf, char const* arg2)
 {
@@ -121,7 +120,7 @@ test_1(QPDF&amp; pdf, char const* arg2)
     bool thrown = false;
     try {
-       i.at("/A");
+        i.at("/A");
     } catch (std::runtime_error const&) {
         thrown = true;
     }
@@ -161,7 +160,9 @@ runtest(int n, char const* filename1, char const* arg2)
     // the test suite to see how the test is invoked to find the file
     // that the test is supposed to operate on.
-    std::set<int> ignore_filename = {1,};
+    std::set<int> ignore_filename = {
+        1,
+    };
     QPDF pdf;
     std::shared_ptr<char> file_buf;
@@ -175,7 +176,8 @@ runtest(int n, char const* filename1, char const* arg2)
     }
     std::map<int, void (*)(QPDF&, char const*)> test_functions = {
-        {0, test_0}, {1, test_1},
+        {0, test_0},
+        {1, test_1},
     };
     auto fn = test_functions.find(n);